We will accurately determine linkages of the NANA's in the MN blood-group antigens and the linkages of the penultimate glactoses to the subjacent sugar which is probably N-acetyl-D-galactosamine, however, it needs to be ruled out conclusively that it is galactose. We plan to completely characterize the infectious mononucleosis receptors and accurately assess their immunodeterminant structure. We will isolate the presumed receptor for an oncogenic virus in sufficient quantity to begin to characterize it immunochemically which may allow us to determine the mode of action of the inhibitory effect of the MN antigens towards a fowl sarcoma virus in vivo. Such a study is also of importance to human oncology. Finally, we will assess the importance of the MN precursor substance in the mouse TA3 cancer for its virulence by immunologic and enzymatic means.